package controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import model.User;
import model.UserDao;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

@WebServlet("/login")
public class LoginServlet extends HttpServlet {
    private ObjectMapper objectMapper=new ObjectMapper();
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf8");
        resp.setCharacterEncoding("utf8");
        //1.获取请求中的参数
        String username=req.getParameter("username");
        String password=req.getParameter("password");

        if(username==null||"".equals(username)||password==null||"".equals(password)){
            //请求的内容缺失,登录失败!
            resp.setContentType("text/html;charset=utf8");
            resp.getWriter().write("当前用户名或密码为空");
            return;
        }
        //2.和数据库中的内容进行比较
        UserDao userDao=new UserDao();
        User user=userDao.selectByName(username);
        if(user==null||!user.getPassword().equals(password)){
            //用户没有查到或密码不匹配,登录失败
            resp.setContentType("text/html;charset=utf8");
            resp.getWriter().write("用户名或密码错误");
            return;
        }
        //3. 如果比较通过,就创建会话.
        HttpSession session=req.getSession(true);
        //把刚才的用户信息存到会话当中
        session.setAttribute("user",user);

        //4.返回一个重定向报文,跳转到博客列表页
        resp.sendRedirect("blog_list.html");
    }

    //这个方法用来检测当前的用户状态

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("application/json;charset=utf8");
        HttpSession session=req.getSession(false);
        if(session==null){
            //检测下会话是否存在,不存在说明未登录
            User user=new User();
            resp.getWriter().write(objectMapper.writeValueAsString(user));
            return ;
        }
        User user= (User) session.getAttribute("user");
        if(user==null){
            //虽然会话有,但是会话里面没有user对象,也视为未登录
            user=new User();
            resp.getWriter().write(objectMapper.writeValueAsString(user));
            return ;
        }
        //已经登录状态
        //注意不要把密码返回给前端
        user.setPassword("");
        resp.getWriter().write(objectMapper.writeValueAsString(user));
    }
}
